1. Field of the Invention
This invention is concerned with polyurethane-based moisture-hardening joint sealing compositions and relates to such a system showing improved stability in storage.
2. Statement of Related Art
Polyurethane-based moisture-hardening sealing compositions have been known for some time. They consist essentially of an isocyanate-terminated polyurethane prepolymer and a swollen thixotropicizing polymer present therein as filler. The stability of sealing compounds such as these in storage is limited by reaction of the isocyanate groups with other constituents or with water diffusing into the composition. In addition, processability can also suffer from the fact that the degree of swelling of the polymer present changes during storage. Accordingly, to ensure safe processability of the compositions, even over prolonged periods, there is a need for products showing increased stability in storage.
Accordingly, the object of the present invention is to provide polyurethane-based moisture-hardening joint sealing compositions which show improved stability in storage.